1. Field of the Invention
The present invention relates to a filler neck cap assembly, especially of an automotive fuel tank, with an approximately pot-shaped insert sealingly insertable into the filler neck end, which insert is provided with projections for engaging in bayonet or helical slots of the filler neck, at its upper end protruding from the filler neck end is circumferentially embraced by a top cap, and contains a pressure vacuum relief valve, which communicates between the filler neck interior and the atmosphere via apertures in the bottom of the insert on the one hand and in the upper end of the insert and/or in the top cap on the other hand, the pressure vacuum relief valve being encased in a self-contained valve housing, which is enclosed in the insert and equipped with a circumferential flange.
2. Background of the Invention
Such a cap assembly is known from U.S. Pat. No. 4,133,346 which shows a filler neck cap assembly with a pressure vacuum relief valve encased in a sheet-metal housing. The sheet-metal housing of the valve is press-fitted into an insertable plastic closure engaging in the filler neck end. This design has the disadvantage that a separate plastic injection-molding process is necessary for manufacture of the insert, and that the pressure vacuum relief valve, once pressed into the insert, can not be replaced without being destroyed. Modular replacement of the valve to select a specified valve function is not possible.